The present invention relates to a water barrier for a shingled roof that is applied to the roof deck, adjacent the eave of the roof, to prevent damage to the roof deck and an interior of a building from wind-blown rain and/or water buildup caused by ice dams or the accumulation of pine needles and leaves along the eave of the roof, and, in particular, to a waterproof roofing membrane, for application adjacent the eave of a roof, that includes an adhesive strip for bonding a lowermost course of asphalt shingles to an upper surface of the waterproof roofing membrane.
In cold climates, the eaves of a house roof or a building with a similar roof structure are normally colder than the upper portion of the roof. This difference in temperature often results in the buildup of snow and water at the eaves of the roof which freezes to form ice dams at the eaves. Water backs up behind the ice dams and, left standing behind the ice dams, leaks down around the nails securing shingles to the roof deck and damages the roof deck and the interior of the home or other building. In warmer climates a buildup of pine needles and leaves along the eaves of a roof can also form a dam that causes a water buildup on the roof which, left standing, leaks down around the nails securing shingles to the roof deck to damage the roof deck and the interior of the home or other building.
To prevent potential costly water damage from water buildup on a roof, waterproof roofing membranes are installed on the roof deck along the lengths of the roof eaves and extending upward from the lower edges of the roof eaves. To provide a waterproof barrier that protects the vulnerable part of the roof from water buildup caused by the presence of ice dams or pine needle and leaf dams, these waterproof roofing membranes are typically about 36 inches wide; are bonded to the deck along the lengths of the roof eaves; and seal around the shanks of nails used to secure asphalt shingles to the roof deck. Examples of such waterproof roofing membranes are waterproof roofing membranes sold by Johns Manville International, Inc., under the trade designations xe2x80x9cROOF DEFENDERxe2x80x9d waterproofing membranes and xe2x80x9cNORDSHIELD and SURE GRIPxe2x80x9d waterproofing membranes.
When applying a lowermost course of asphalt shingles to a roof deck over one of these waterproof roofing membranes, a typical procedure followed by roofers to help seal and hold down the lowermost course of asphalt shingles at an eave edge, where the lift from winds may be the most severe, includes the following steps. Tabs are cut off or removed from a number of asphalt shingles whose combined length equals the length of the eave. The remainder of each asphalt shingle, typically about half of the asphalt shingle in width, is inverted or turned upside down so that the adhesive on what is normally the underside of the shingle, typically used to help secure the asphalt shingle to an underlayment, faces upward and these half shingles are nailed to the roof deck along the lower edge of the eave for the length of the eave. The first or lowermost course of full size asphalt shingles is then applied over these partial asphalt shingles and nailed to the roof deck with the adhesive on the now upper surfaces of the inverted partial asphalt shingles bonding to the undersides of the lowermost course of full size asphalt shingles to help seal and hold the lowermost course of asphalt shingles in place on the roof deck. While this procedure for applying the lowermost course of full size asphalt shingles to a roof deck is effective, the procedure is labor intensive and time consuming and there has remained a need to help seal and hold down a lowermost course of asphalt shingles on a roof deck that eliminates or greatly reduces the time and labor required to prepare the roof for the application of the lowermost course of full size shingles to the roof deck.
The waterproof roofing membrane of the present invention provides an inexpensive, labor and time saving solution to the above discussed problems. The waterproof roofing membrane of the present invention, which prevents water damage to a roof deck and an interior of a building through leakage from water buildup on an asphalt shingled roof, is preferably made of a fibrous mat, e.g. a glass fiber mat, saturated with a bituminous material. The waterproof roofing membrane is both waterproof and seals around nail penetrations through the membrane to form a watertight barrier.
The waterproof roofing membrane includes a first major surface with an adhesive thereon for bonding the waterproof roofing membrane to a roof deck along a lower portion of the roof deck adjacent the lower edge of the eave of the roof deck and a second major surface with an adhesive strip thereon for sealing a lowermost course of asphalt shingles to the membrane and helping to hold down this course of shingles which is more susceptible than other courses of shingles to being lifted off the roof deck by high winds. Preferably, the adhesive on the first major surface of the waterproof roofing membrane is coextensive with the first major surface of the membrane. A release sheet or film, which is removed immediately prior to applying and bonding the waterproof roofing membrane to a roof deck, covers the adhesive during storage, shipment and handling. Preferably, the adhesive on the second major surface of the waterproof roofing membrane is a strip of adhesive extending for the length of the membrane adjacent a lateral edge of the membrane adapted to be the lower lateral edge of the membrane, i.e. a lateral edge of the membrane that extends along the lower edge of a roof eave when the membrane is installed. The adhesive strip is a generally continuous layer or a patterned layer. A release sheet or film, which is removed immediately prior to applying and bonding the lowermost course of asphalt shingles to the waterproof roofing membrane, covers the adhesive layer during storage, shipment and handling.